Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Question could someone help me

  1. Feb 27, 2009 #1
    hiii every body

    i have Home Work could some one help me to solve this Question" or give me the guide

    X, Y and Z are continuous random variables with joint density

    F(x,y,z)= {(3/32 x^2) y+[1/48(x+y)z For 0<x<2,
    elswhere =0

    1) find the marginal of x,y and z
    2)find E(x), E(y) and E(z)

  2. jcsd
  3. Feb 27, 2009 #2
    Someone shortly will tell you to post this in the homework section. To get the expectation of x integrate the x*F(x,y,z) over the domain. I forgot what the marginal is but looking at wikipedia it seems to be the distribution of a subset of the other random variables. So I presume to get the marginal in tems of x you integrate out the y and z variables.
  4. Feb 27, 2009 #3
    John Creighto thank u dear
  5. Feb 28, 2009 #4
    Apologize to forget to provide attempt part:

    1) find the marginal of x,y and z:
    i have try to integrate x and y together
    then the result be numbers with i reintegrate z to find the result
    i don't know if this way is true

    2)find E(x), E(y) and E(z)
    this question provide with 3 variable and i know only to solve by 2 variable

    someone help me please
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook